Contrast-enhanced ultrasonography and endoscopic ultrasonography in the diagnosis of pancreatic disorders

Contrast-enhanced ultrasonography in the diagnosis of pancreatic disorders should be reviewed with regard to the development, varieties of contrast agents, and also ultrasound technologies. Contrast agents for ultrasonography are roughly divided into two categories: Those effective in the digestive tract and those in the vessels (arteries and veins). The former include the water-like material to bring proper acoustic windows between the US probe and pancreas. The latter are those including carbon dioxide microbubbles injected into the arteries (not used nowadays) and contrast agents effective after injection into peripheral veins (today's mainstream). As to the ultrasonographic technologies, color/power Doppler imaging and harmonic imaging have brought about a big change in the investigation of the hemodynamics of lesions. In addition, collaboration between novel US technologies and endosonoscopes with an electronic scanning probe has opened the door for far more accurate diagnosis evaluating hemodynamics in the diagnosis of pancreatic disorders. Here, we describe in this review the outline of a historical view and future perspective of contrast-enlianced US and EUS.